System and method for prevention of wireless charging cross connection

ABSTRACT

A system and method for charging a chargeable device is provided. The system can include a wireless charger including a wireless power transmitter d configured to generate a wireless charging field in at least one charging region. The wireless charger further includes a transceiver configured to communicate with the chargeable device. The wireless charger further includes a controller configured to facilitate avoidance of cross connection of the chargeable device with the wireless charger and at least one other wireless charger by initiating a disconnection of a communication link between the wireless charger and the chargeable device based at least in part on a comparison of a detected power level of the wireless charger to a predetermined level indicative of saturation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/747,311 filed Jun. 23, 2015, which claims the benefit of priority toU.S. Provisional Appl. No. 62/059,683, filed Oct. 3, 2014, both of whichare incorporated in their entireties by reference herein.

FIELD

The present invention relates generally to wireless power. Morespecifically, the disclosure is directed to systems, methods, anddevices for establishing communications between a wireless powerreceiver and a wireless power transmitter where the receiver may bepositioned within the wireless charging region of the transmitter but iscapable of establishing communications with one or more additionalwireless power transmitters.

BACKGROUND

An increasing number and variety of electronic devices are powered viarechargeable batteries. Such devices include mobile phones, portablemusic players, laptop computers, tablet computers, computer peripheraldevices, communication devices (e.g., Bluetooth devices), digitalcameras, hearing aids, and the like. While battery technology hasimproved, battery-powered electronic devices increasingly require andconsume greater amounts of power, thereby often requiring recharging.Rechargeable devices are often charged via wired connections throughcables or other similar connectors that are physically connected to apower supply. Cables and similar connectors may sometimes beinconvenient or cumbersome and have other drawbacks. Wireless chargingsystems that are capable of transferring power in free space to be usedto charge rechargeable electronic devices or provide power to electronicdevices may overcome some of the deficiencies of wired chargingsolutions. As such, wireless power transfer systems and methods thatefficiently and safely transfer power to electronic devices aredesirable.

SUMMARY

Various implementations of systems, methods and devices within the scopeof the appended claims each have several aspects, no single one of whichis solely responsible for the desirable attributes described herein.Without limiting the scope of the appended claims, some prominentfeatures are described herein.

Details of one or more implementations of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings, and the claims. Note thatthe relative dimensions of the following figures may not be drawn toscale.

One aspect of the disclosure provides a wireless charger for wirelesslycharging a chargeable device. The wireless charger comprises a wirelesspower antenna. The wireless charger further comprises a wireless powertransmitter coupled to the wireless power antenna and configured togenerate a wireless charging field in at least one charging region. Thewireless charger further comprises a communication antenna and atransceiver coupled to the communication antenna and configured tocommunicate with the chargeable device via the communication antenna.The wireless charger further comprises a controller configured tofacilitate avoidance of cross connection of the chargeable device withthe wireless charger and at least one other wireless charger by using atleast one of the following: (i) selectively accepting or refusing a dataconnection between the wireless charger and the chargeable device basedat least in part on at least one of: (a) comparison of an area of thechargeable device to a free amount of the at least one charging region;or (b) determination of whether a request to enable a data connection iswithin a predetermined acceptance time window; or (c) determination ofwhether any requests to enable a data connection have been previouslyreceived; or (d) determination of which request to enable a dataconnection has the strongest data signal; or (ii) forcing adisconnection of the wireless charger from the chargeable device basedat least in part on a comparison of a detected power level of thewireless charger to a predetermined level indicative of saturation; or(iii) turning on the wireless charger after a corresponding random timeperiod has elapsed; or (iv) delay of the acceptance time window if adetected indication of the chargeable device is within the at least onecharging region is less than a predetermined value; or any combinationthereof.

Another aspect of the disclosure provides a wireless charger forwirelessly charging a chargeable device. The wireless charger comprisesmeans for generating a wireless charging field in at least one chargingregion. The wireless charger further comprises means for communicatingwith the chargeable device. The wireless charger further comprises meansfor facilitating avoidance of cross connection of the chargeable devicewith the wireless charger and at least one other wireless charger byusing at least one of the following: (i) selectively accepting orrefusing a data connection between the wireless charger and thechargeable device based at least in part on at least one of: (a)comparison of an area of the chargeable device to a free amount of theat least one charging region; or (b) determination of whether a requestto enable a data connection is within a predetermined acceptance timewindow; or (c) determination of whether any requests to enable a dataconnection have been previously received; or (d) determination of whichrequest to enable a data connection has the strongest data signal; or(ii) forcing a disconnection of the wireless charger from the chargeabledevice based at least in part on a comparison of a detected power levelof the wireless charger to a predetermined level indicative ofsaturation; or (iii) turning on the wireless charger after acorresponding random time period has elapsed; or (iv) delay of theacceptance time window if a detected indication of the chargeable deviceis within the at least one charging region is less than a predeterminedvalue; or any combination thereof.

Another aspect of the disclosure provides a non-transitorycomputer-readable medium comprising code that, when executed, causes awireless charger to generate a wireless charging field in at least onecharging region. The medium further comprises code that, when executed,causes the wireless charger to communicate with the chargeable device.The medium further comprises code that, when executed, causes thewireless charger to facilitate avoidance of cross connection of thechargeable device with the wireless charger and at least one otherwireless charger by using at least one of the following: (i) selectivelyaccepting or refusing a data connection between the wireless charger andthe chargeable device based at least in part on at least one of: (a)comparison of an area of the chargeable device to a free amount of theat least one charging region; or (b) determination of whether a requestto enable a data connection is within a predetermined acceptance timewindow; or (c) determination of whether any requests to enable a dataconnection have been previously received; or (d) determination of whichrequest to enable a data connection has the strongest data signal; or(ii) forcing a disconnection of the wireless charger from the chargeabledevice based at least in part on a comparison of a detected power levelof the wireless charger to a predetermined level indicative ofsaturation; or (iii) turning on the wireless charger after acorresponding random time period has elapsed; or (iv) delay of theacceptance time window if a detected indication of the chargeable deviceis within the at least one charging region is less than a predeterminedvalue; or any combination thereof.

Another aspect of the disclosure provides a method for wirelesslycharging a chargeable device. The method comprises generating a wirelesscharging field in at least one charging region. The wireless chargingfield comprises a plurality of power signals. The method furthercomprises communicating with the chargeable device. The method furthercomprises facilitating avoidance of cross connection of the chargeabledevice with a wireless charger and at least one other wireless chargerin which the chargeable device receives power from one of the wirelesscharger or the at least one other wireless charger while communicatingwith the other of the wireless charger or the at least one otherwireless charger. Facilitating avoidance of cross connection uses atleast one of the following: comparison of a detected power level to apredetermined level indicative of saturation; or turning on the wirelesscharger after a corresponding random time period has elapsed; comparisonof an area of the chargeable device to a free amount of the at least onecharging region; or determination of whether a request to enable a dataconnection is within a predetermined acceptance time window; or delay ofthe acceptance time window if a detected indication of the chargeabledevice is within the at least one charging region is less than apredetermined value; or determination of whether any requests to enablea data connection have been previously received; or determination ofwhich request to enable a data connection has the strongest data signal;or any combination thereof.

Another aspect of the disclosure provides a wireless charger forwirelessly charging a chargeable device. The wireless charger comprisesa wireless power transmitter configured to generate a wireless chargingfield in at least one charging region. The wireless charger furthercomprises a transceiver configured to communicate with the chargeabledevice. The wireless charger further comprises a controller configuredto facilitate avoidance of cross connection of the chargeable devicewith the wireless charger and at least one other wireless charger byinitiating a disconnection of a communication link between the wirelesscharger and the chargeable device based at least in part on a comparisonof a detected transmitted power level of the wireless charger to atleast one predetermined level indicative of at least one saturationcondition.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises detecting a transmittedpower level of a wireless charger. The method further comprisescomparing the detected transmitted power level to at least onepredetermined level indicative of at least one saturation condition. Themethod further comprises initiating a disconnection of a communicationlink between the wireless charger and the chargeable device based atleast in part on whether the at least one saturation condition exists.

Another aspect of the disclosure provides a wireless charger comprisingmeans for generating a wireless charging field in at least one chargingregion. The wireless charger further comprises means for communicatingwith a chargeable device. The wireless charger further comprise meansfor facilitating avoidance of cross connection of the chargeable devicewith the wireless charger and at least one other wireless charger byinitiating a disconnection of a communication link between the wirelesscharger and the chargeable device based at least in part on a comparisonof a detected transmitted power level of the wireless charger to atleast one predetermined level indicative of at least one saturationcondition.

Another aspect of the disclosure provides a non-transitorycomputer-readable medium comprising code that, when executed, causes awireless charger to generate a wireless charging field in at least onecharging region. The code, when executed, further causes the wirelesscharger to communicate with a chargeable device. The code, whenexecuted, further causes the wireless charger to facilitate avoidance ofcross connection of the chargeable device with the wireless charger andat least one other wireless charger by initiating a disconnection of acommunication link between the wireless charger and the chargeabledevice based at least in part on a comparison of a detected transmittedpower level of the wireless charger to at least one predetermined levelindicative of at least one saturation condition.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises, for each wireless chargerof a plurality of wireless chargers operatively coupled to a commonpower circuit, setting a random value for a time period between (i)power being provided to the wireless charger via the common powercircuit and (ii) the wireless charger being turned on. The methodfurther comprises, upon power being provided to the common powercircuit, turning on each wireless charger of the plurality of thewireless chargers after its corresponding random time period haselapsed.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises determining a chargingarea of a wireless charger. The method further comprises, for eachchargeable device that attempts to connect to the wireless charger,comparing an area of the chargeable device to a free amount of thecharging area. The method further comprises accepting or rejecting theconnection between the chargeable device and the wireless charger inresponse at least in part to the comparison. The method furthercomprises, in response to accepting a connection between a chargeabledevice and the wireless charger or in response to termination of aconnection between a chargeable device and the wireless charger,revising the amount of the charging area that is free to accept achargeable device.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises defining an acceptancetime window for the wireless charger, the acceptance time windowoccurring after a chargeable device positioned within a charging regionof the wireless charger detects power from the wireless charger, theacceptance time window having a first endpoint at a first predeterminedamount of time after power is applied to the wireless charger and asecond endpoint at a second predetermined amount of time after power isapplied to the wireless charger. The method further comprises receivinga request to enable a data connection from a chargeable device. Themethod further comprises determining whether the request occurs withinthe acceptance time window. The method further comprises accepting orrejecting the data connection in response to whether the request occurswithin the acceptance time window or not.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises defining an acceptancetime window for the wireless charger, the acceptance time windowoccurring after a chargeable device positioned within a charging regionof the wireless charger detects power from the wireless charger, theacceptance time window having a first endpoint at a first predeterminedamount of time after power is applied to the wireless charger and asecond endpoint at a second predetermined amount of time after power isapplied to the wireless charger. The method further comprises receivinga request to enable a data connection from a chargeable device. Themethod further comprises detecting an indication of whether thechargeable device is within the charging region of the wireless chargerand comparing the indication to a predetermined value. The methodfurther comprises delaying the acceptance time window by a predeterminedamount of time if the detected indication is inconclusive regardingwhether the chargeable device is within the charging region of thewireless charger. The method further comprises determining whether therequest occurs within the acceptance time window. The method furthercomprises accepting or rejecting the data connection in response towhether the request occurs within the acceptance time window or not.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises receiving a request toenable a data connection from a chargeable device. The method furthercomprises determining whether any requests have been previously receivedbefore having received the request from the chargeable device. Themethod further comprises accepting the data connection if no requestshave been previously received before having received the request fromthe chargeable device.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises transmitting a requestfrom the wireless charger to enable a data connection with thechargeable device. The method further comprises using the chargeabledevice to determine whether a previous connection of the chargeabledevice to the wireless charger resulted in cross connection. The methodfurther comprises preventing initiation (e.g., aborting or notinitiating) of the request if the previous connection resulted in crossconnection.

Another aspect of the disclosure provides a method of facilitatingavoidance of cross connection of a chargeable device in communicationwith a wireless charger. The method comprises receiving one or morerequests to enable a data connection from one or more chargeabledevices. The method further comprises determining which request has thestrongest data signal of the one or more requests. The method furthercomprises accepting the data connection corresponding to the strongestdata signal of the one or more requests.

Another aspect of the disclosure provides a wireless charger forwirelessly charging a chargeable device. The wireless charger includes awireless power transmitter coupled to a wireless power antenna andconfigured to generate a wireless charging field in at least onecharging region. The wireless charger further includes a transceivercoupled to a communication antenna and configured to wirelesslycommunicate with the chargeable device via a communication channelestablished between the transceiver and the chargeable device. Thetransceiver is configured to receive one or more requests from thechargeable devices for a requested change of a transmitted power levelof the wireless power transmitter. The wireless charger further includesa controller configured to receive information indicative of at leastone saturation condition of the wireless power transmitter based on thetransmitted power level of the wireless power transmitter. Thecontroller is further configured to cause a disconnection of thecommunication channel between the transceiver and with the chargeabledevice based at least in part on the information indicative of the atleast one saturation condition and the one or more requests from thechargeable device for a requested change of the transmitter power levelof the wireless power transmitter.

Another aspect of the disclosure further provides a method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger. The method includes receivinginformation indicative of at least one saturation condition of awireless power transmitter of the wireless charger based on atransmitted power level of the wireless power transmitter. The methodfurther includes causing a disconnection of a communication channelbetween the wireless charger and the chargeable device based at least inpart on the information indicative of the at least one saturationcondition and one or more requests by the chargeable device for arequested change of the transmitted power level of the wireless powertransmitter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of an exemplary wireless powertransfer system, in accordance with exemplary embodiments of theinvention.

FIG. 2 is a functional block diagram of exemplary components that may beused in the wireless power transfer system of FIG. 1, in accordance withvarious exemplary embodiments of the invention.

FIG. 3 is a schematic diagram of a portion of transmit circuitry orreceive circuitry of FIG. 2 including a transmit or receive antenna, inaccordance with exemplary embodiments of the invention.

FIG. 4 is a functional block diagram of a transmitter that may be usedin the wireless power transfer system of FIG. 1, in accordance withexemplary embodiments of the invention.

FIG. 5 is a functional block diagram of a receiver that may be used inthe wireless power transfer system of FIG. 1, in accordance withexemplary embodiments of the invention.

FIG. 6 is a schematic diagram of a portion of transmit circuitry thatmay be used in the transmit circuitry of FIG. 4.

FIG. 7A is a functional block diagram of a receiver in the presence ofmultiple transmitters, in accordance with exemplary embodiments of theinvention.

FIG. 7B schematically illustrates an example of cross connection amongfour receivers in the presence of two transmitters.

FIG. 7C is a block diagram of a wireless charging system that mayincorporate the transmit circuitry of FIG. 4 and the receive circuitryof FIG. 5.

FIG. 8 is a timing and signal flow diagram of communications between awireless charger and a chargeable device, such as the wireless chargerand the chargeable device of FIG. 7A, to establish a connection betweenthe wireless charger and the chargeable device.

FIG. 9 is a flow diagram of an example first resolution method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

FIG. 10 is a flow diagram of an example of a second resolution method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

FIG. 11 is a flow diagram of an example of a third resolution method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

FIG. 12 is a flow diagram of an example of a fourth resolution method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

FIG. 13 is a flow diagram of an example of a fifth resolution method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

FIG. 14 is a flow diagram of an example of a sixth resolution method offacilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

FIG. 15 is a flow diagram of an example of a seventh resolution methodof facilitating avoidance of cross connection of a chargeable device incommunication with a wireless charger in accordance with certainembodiments described herein.

The various features illustrated in the drawings may not be drawn toscale. Accordingly, the dimensions of the various features may bearbitrarily expanded or reduced for clarity. In addition, some of thedrawings may not depict all of the components of a given system, methodor device. Finally, like reference numerals may be used to denote likefeatures throughout the specification and figures.

DETAILED DESCRIPTION

In some wireless power systems, and as will be described below, thetransmitter and receiver communicate on a frequency other than thatbeing used to transfer power. In some embodiments, it is desirable toestablish this so-called out-of-band communication channel independentof the wireless power field used to transfer power. The out-of-bandcommunication channel is useful to reduce the complexity of the in-bandtransmitter and receiver circuitry. Because in-band power transfer andthe out-of-band communication channel have different characteristics, areceiver may be out of out of range for wireless power from atransmitter but within range for out-of-band communication. As a result,when multiple transmitters are present within a given space, crossconnection can result, where a power transmitter sends power to a powerreceiver but connects its control signal to another power receiver, or apower receiver is powered by a power transmitter but has a controlsignal connected to another power transmitter. This condition can leadto unstable operation, loss of efficiency, and poor user experience.Thus, it is desirable to avoid such cross connection or to detect andremedy such cross connection and initiate proper communication among thevarious devices.

The detailed description set forth below in connection with the appendeddrawings is intended as a description of exemplary embodiments of theinvention and is not intended to represent the only embodiments in whichthe invention may be practiced. The term “exemplary” used throughoutthis description means “serving as an example, instance, orillustration,” and should not necessarily be construed as preferred oradvantageous over other exemplary embodiments. The detailed descriptionincludes specific details for the purpose of providing a thoroughunderstanding of the exemplary embodiments of the invention. In someinstances, some devices are shown in block diagram form.

Wirelessly transferring power may refer to transferring any form ofenergy associated with electric fields, magnetic fields, electromagneticfields, or otherwise from a transmitter to a receiver without the use ofphysical electrical conductors (e.g., power may be transferred throughfree space). The power output into a wireless field (e.g., a magneticfield) may be received, captured by, or coupled by a “receiving antenna”to achieve power transfer.

FIG. 1 is a functional block diagram of an exemplary wireless powertransfer system 100, in accordance with exemplary embodiments of theinvention. Input power 102 may be provided to a transmitter 104 from apower source (not shown) for generating a field 105 for providing energytransfer. A receiver 108 may couple to the field 105 and generate outputpower 110 for storing or consumption by a device (not shown) coupled tothe output power 110. Both the transmitter 104 and the receiver 108 areseparated by a distance 112. In one exemplary embodiment, transmitter104 and receiver 108 are configured according to a mutual resonantrelationship. When the resonant frequency of receiver 108 and theresonant frequency of transmitter 104 are substantially the same or veryclose, transmission losses between the transmitter 104 and the receiver108 are reduced. As such, wireless power transfer may be provided overlarger distance in contrast to purely inductive solutions that mayrequire large coils to be very close (e.g., millimeters). Resonantinductive coupling techniques may thus allow for improved efficiency andpower transfer over various distances and with a variety of inductivecoil configurations.

The receiver 108 may receive power when the receiver 108 is located inan energy field 105 produced by the transmitter 104. The field 105corresponds to a region where energy output by the transmitter 104 maybe captured by a receiver 108. The transmitter 104 may include atransmit antenna 114 for outputting an energy transmission. The receiver108 further includes a receive antenna 118 for receiving or capturingenergy from the energy transmission. In some cases, the field 105 maycorrespond to the “near-field” of the transmitter 104. The near-fieldmay correspond to a region in which there are strong reactive fieldsresulting from the currents and charges in the transmit antenna 114 thatminimally radiate power away from the transmit antenna 114. In somecases the near-field may correspond to a region that is within about onewavelength (or a fraction thereof) of the transmit antenna 114.Efficient energy transfer may occur by coupling a large portion of theenergy in a field 105 of the transmit antenna 114 to a receive antenna118 rather than propagating most of the energy in an electromagneticwave to the far field. The transmit and receive antennas 114 and 118 aresized according to applications and devices to be associated therewith.When positioned within the field 105, a “coupling mode” may be developedbetween the transmit antenna 114 and the receive antenna 118.

In one embodiment, the transmitter 104 may be configured to output atime varying magnetic field with a frequency corresponding to theresonant frequency of the transmit antenna 114. When the receiver iswithin the field 105, the time varying magnetic field may induce acurrent in the receive antenna 118. As described above, if the receiveantenna 118 is configured to be resonant at the frequency of thetransmit antenna 118, energy may be efficiently transferred. The ACsignal induced in the receive antenna 118 may be rectified as describedabove to produce a DC signal that may be provided to charge or to powera load.

FIG. 2 is a functional block diagram of exemplary components that may beused in the wireless power transfer system 100 of FIG. 1, in accordancewith various exemplary embodiments of the invention. In the wirelesspower transfer system 200, the transmitter 204 may include transmitcircuitry 206 that may include an oscillator 222, a driver circuit 224,and a filter and matching circuit 226. The oscillator 222 may beconfigured to generate a signal at a desired frequency, such as 468.75KHz, 6.78 MHz or 13.56 MHz, that may be adjusted in response to afrequency control signal 223. The oscillator signal may be provided to adriver circuit 224 configured to drive the transmit antenna 214 at, forexample, a resonant frequency of the transmit antenna 214. The drivercircuit 224 may be a switching amplifier configured to receive a squarewave from the oscillator 222 and output a sine wave. For example, thedriver circuit 224 may be a class E amplifier. A filter and matchingcircuit 226 may be also included to filter out harmonics or otherunwanted frequencies and match the impedance of the transmitter 204 tothe transmit antenna 214. As a result of driving the transmit antenna214, the transmitter 204 may wirelessly output power at a levelsufficient for charging or powering an electronic device. As oneexample, the power provided may be for example on the order of 300milliWatts to 10-20 Watts to power or charge different devices withdifferent power requirements. Higher or lower power levels may also beprovided.

The receiver 208 may include receive circuitry 210 that may include amatching circuit 232 and a rectifier and switching circuit 234 togenerate a DC power output from an AC power input to charge a battery236 as shown in FIG. 2 or to power a device (not shown) coupled to thereceiver 108. The matching circuit 232 may be included to match theimpedance of the receive circuitry 210 to the receive antenna 218. Thereceiver 208 and transmitter 204 may additionally communicate on aseparate communication channel 219 (e.g., Bluetooth, zigbee, cellular,etc). The receiver 208 and transmitter 204 may alternatively communicatevia in-band signaling using characteristics of the wireless field 205.

As described more fully below, receiver 208, that may initially have aselectively disablable associated load (e.g., battery 236), may beconfigured to determine whether an amount of power transmitted bytransmitter 204 and received by receiver 208 is appropriate for charginga battery 236. Further, receiver 208 may be configured to enable a load(e.g., battery 236) upon determining that the amount of power isappropriate. In some embodiments, a receiver 208 may be configured todirectly utilize power received from a wireless power transfer fieldwithout charging of a battery 236. For example, a communication device,such as a near-field communication (NFC) or radio-frequencyidentification device (RFID may be configured to receive power from awireless power transfer field and communicate by interacting with thewireless power transfer field and/or utilize the received power tocommunicate with a transmitter 204 or other devices.

FIG. 3 is a schematic diagram of a portion of transmit circuitry 206 orreceive circuitry 210 of FIG. 2 including a transmit or receive antenna352, in accordance with exemplary embodiments of the invention. Asillustrated in FIG. 3, transmit or receive circuitry 350 used inexemplary embodiments including those described below may include anantenna 352. The antenna 352 may also be referred to or be configured asa “loop” antenna 352. The antenna 352 may also be referred to herein orbe configured as a “magnetic” antenna or an induction coil. The term“antenna” generally refers to a component that may wirelessly output orreceive energy for coupling to another “antenna.” The antenna may alsobe referred to as a coil of a type that is configured to wirelesslyoutput or receive power. As used herein, an antenna 352 is an example ofa “power transfer component” of a type that is configured to wirelesslyoutput and/or receive power. The antenna 352 may be configured toinclude an air core or a physical core such as a ferrite core (notshown).

The transmit or receive circuitry 350 may be configured as a resonantcircuit/structure for resonant inductive power transfer as disclosedabove. The resonant frequency of the transmit or receive circuitry 350is based on the inductance and capacitance. Inductance may be simply theinductance created by the antenna 352, whereas, capacitance may be added(e.g., an additional capacitor in some cases) to create a resonantstructure at a desired resonant frequency. As a non-limiting example,capacitor 354 and capacitor 356 may be added to the transmit or receivecircuitry 350 to create a resonant circuit that resonates at a resonantfrequency (e.g., the operating frequency output by any drivingcircuitry, an example of which is the driver circuit 224 of FIG. 2).Accordingly, for larger diameter antennas, the size of capacitanceneeded to sustain resonance may decrease as the diameter or inductanceof the loop increases. Furthermore, as the diameter of the antennaincreases, the efficient energy transfer area of the near-field mayincrease. Other resonant circuits formed using other components are alsopossible. Series or parallel (shunt) resonant circuits may be used inaccordance with embodiments described herein. As a non-limiting example,a capacitor may be placed in parallel between the two terminals of theantenna 352. For transmit antennas, a signal 358 with a frequency thatsubstantially corresponds to the resonant frequency of the antenna 352may be an input to the antenna 352. For a receive antennas, the signal358, with a frequency that substantially corresponds to the resonantfrequency of the antenna 352, may be an output from the antenna 352.

FIG. 4 is a functional block diagram of a transmitter 404 that may beused in the wireless power transfer system of FIG. 1, in accordance withexemplary embodiments of the invention. The transmitter 404 may includetransmit circuitry 406 and a transmit antenna 414. The transmit antenna414 may be the antenna 352 as shown in FIG. 3. Transmit circuitry 406may provide power to the transmit antenna 414 by providing anoscillating signal resulting in generation of energy (e.g., magneticflux) about the transmit antenna 414. Transmitter 404 may operate at anysuitable frequency. By way of example, transmitter 404 may operate atthe 6.78 MHz ISM band.

Transmit circuitry 406 may include a fixed impedance matching circuit409 for matching the impedance of the transmit circuitry 406 (e.g., 50ohms) to the transmit antenna 414 and a low pass filter (LPF) 408configured to reduce harmonic emissions to levels to preventself-jamming of devices coupled to receivers 108 (FIG. 1). Otherexemplary embodiments may include different filter topologies, includingbut not limited to, notch filters that attenuate specific frequencieswhile passing others and may include an adaptive impedance match, thatmay be varied based on measurable transmit metrics, such as output powerto the antenna 414 or DC current drawn by the driver circuit 424.Transmit circuitry 406 further includes a driver circuit 424 (e.g.,power amplifier) configured to drive an RF signal as determined by anoscillator 423. The transmit circuitry 406 may be comprised of discretedevices or circuits, or alternately, may be comprised of an integratedassembly. An exemplary RF power output from transmit antenna 414 may beon the order of 2.5 Watts or higher (e.g., from 10-60 Watts or even from11-10 kWatts).

Transmit circuitry 406 may further include a controller 415 forselectively enabling the oscillator 423, for adjusting the frequency orphase of the oscillator 423, and for adjusting the output power levelfor implementing a communication protocol for interacting withneighboring devices through their attached receivers. The controller 415can be operatively coupled to a memory 470. It is noted that thecontroller 415 may also be referred to herein as a processor. Adjustmentof oscillator phase and related circuitry in the transmission path mayallow for reduction of out of band emissions, especially whentransitioning from one frequency to another.

The transmit circuitry 406 may further include a load sensing circuit416 for detecting the presence or absence of active receivers in thevicinity of the near-field generated by transmit antenna 414. By way ofexample, a load sensing circuit 416 monitors the current flowing to thedriver circuit 424, that may be affected by the presence or absence ofactive receivers in the vicinity of the field generated by transmitantenna 414 as will be further described below. Detection of changes tothe loading on the driver circuit 424 are monitored by controller 415for use in determining whether to enable the oscillator 423 fortransmitting energy and to communicate with an active receiver. Asdescribed more fully below, a current measured at the driver circuit 424may be used to determine whether an invalid device is positioned withina wireless power transfer region of the transmitter 404.

The transmit antenna 414 may be implemented with a Litz wire or as anantenna strip with the thickness, width and metal type selected to keepresistive losses low. In a one implementation, the transmit antenna 414may generally be configured for association with a larger structure suchas a table, mat, lamp or other less portable configuration. Accordingly,the transmit antenna 414 generally may not need “turns” in order to beof a practical dimension. An exemplary implementation of a transmitantenna 414 may be “electrically small” (i.e., fraction of thewavelength) and tuned to resonate at lower usable frequencies by usingcapacitors to define the resonant frequency.

The transmitter 404 may gather and track information about thewhereabouts and status of receiver devices that may be associated withthe transmitter 404. Thus, the transmit circuitry 406 may include apresence detector 480, an enclosed detector 460, or a combinationthereof, connected to the controller 415 (also referred to as aprocessor herein). The controller 415 may adjust an amount of powerdelivered by the driver circuit 424 in response to presence signals fromthe presence detector 480 and the enclosed detector 460. The transmitter404 may receive power through a number of power sources, such as, forexample, an AC-DC converter (not shown) to convert AC power present in abuilding, a DC-DC converter (not shown) to convert a DC power source toa voltage suitable for the transmitter 404, or directly from a DC powersource (not shown).

As a non-limiting example, the presence detector 480 may be a motiondetector utilized to sense the initial presence of a device to becharged that is inserted into the coverage area of the transmitter 404.After detection, the transmitter 404 may be turned on and the RF powerreceived by the device may be used to toggle a switch on the Rx devicein a pre-determined manner, which in turn results in changes to thedriving point impedance of the transmitter 404. Further, the presencedetector 480 may be used to ensure that a device to be charged that iscommunicating with the transmitter 404 is the one that has been recentlyplaced into the coverage area of the transmitter 404.

As another non-limiting example, the presence detector 480 may be adetector capable of detecting a human, for example, by infrareddetection, motion detection, or other suitable means. In some exemplaryembodiments, there may be regulations limiting the amount of power thata transmit antenna 414 may transmit at a specific frequency. In somecases, these regulations are meant to protect humans fromelectromagnetic radiation. However, there may be environments where atransmit antenna 414 is placed in areas not occupied by humans, oroccupied infrequently by humans, such as, for example, garages, factoryfloors, shops, and the like. If these environments are free from humans,it may be permissible to increase the power output of the transmitantenna 414 above the normal power restrictions regulations. In otherwords, the controller 415 may adjust the power output of the transmitantenna 414 to a regulatory level or lower in response to human presenceand adjust the power output of the transmit antenna 414 to a level abovethe regulatory level when a human is outside a regulatory distance fromthe field of the transmit antenna 414.

As a non-limiting example, the enclosed detector 460 (may also bereferred to herein as an enclosed compartment detector or an enclosedspace detector) may be a device such as a sense switch for determiningwhen an enclosure is in a closed or open state. When a transmitter is inan enclosure that is in an enclosed state, a power level of thetransmitter may be increased.

In exemplary embodiments, a method by which the transmitter 404 does notremain on indefinitely may be used. In this case, the transmitter 404may be programmed to shut off after a user-determined amount of time.This feature prevents the transmitter 404, notably the driver circuit424, from running long after the wireless devices in its perimeter arefully charged. This event may be due to the failure of the circuit todetect the signal sent from either the repeater or the receive antenna218 that a device is fully charged. To prevent the transmitter 404 fromautomatically shutting down if another device is placed in itsperimeter, the transmitter 404 automatic shut off feature may beactivated only after a set period of lack of motion detected in itsperimeter. The user may be able to determine the inactivity timeinterval, and change it as desired. As a non-limiting example, the timeinterval may be longer than that needed to fully charge a specific typeof wireless device under the assumption of the device being initiallyfully discharged.

FIG. 5 is a functional block diagram of a receiver 508 that may be usedin the wireless power transfer system of FIG. 1, in accordance withexemplary embodiments of the invention. The receiver 508 includesreceive circuitry 510 that may include a receive antenna 518. Receiver508 further couples to device 550 for providing received power thereto.It should be noted that receiver 508 is illustrated as being external todevice 550 but may be integrated into device 550. Energy may bepropagated wirelessly to receive antenna 518 and then coupled throughthe rest of the receive circuitry 510 to device 550. By way of example,the chargeable device may include devices such as mobile phones,portable music players, laptop computers, tablet computers, computerperipheral devices, communication devices (e.g., Bluetooth devices),digital cameras, hearing aids (and other medical devices), and the like.

Receive antenna 518 may be tuned to resonate at the same frequency, orwithin a specified range of frequencies, as transmit antenna 414 (FIG.4). Receive antenna 518 may be similarly dimensioned with transmitantenna 414 or may be differently sized based upon the dimensions of theassociated device 550. By way of example, device 550 may be a portableelectronic device having diametric or length dimension smaller than thediameter or length of transmit antenna 414. In such an example, receiveantenna 518 may be implemented as a multi-turn coil in order to reducethe capacitance value of a tuning capacitor (not shown) and increase thereceive antenna's impedance. By way of example, receive antenna 518 maybe placed around the substantial circumference of device 550 in order tomaximize the antenna diameter and reduce the number of loop turns (i.e.,windings) of the receive antenna 518 and the inter-winding capacitance.

Receive circuitry 510 may provide an impedance match to the receiveantenna 518. Receive circuitry 510 includes power conversion circuitry506 for converting a received RF energy source into charging power foruse by the device 550. Power conversion circuitry 506 includes anRF-to-DC converter 520 and may also include a DC-to-DC converter 522.RF-to-DC converter 520 rectifies the RF energy signal received atreceive antenna 518 into a non-alternating power with an output voltagerepresented by V_(rect). The DC-to-DC converter 522 (or other powerregulator) converts the rectified RF energy signal into an energypotential (e.g., voltage) that is compatible with device 550 with anoutput voltage and output current represented by V_(out) and I_(out).Various RF-to-DC converters are contemplated, including partial and fullrectifiers, regulators, bridges, doublers, as well as linear andswitching converters.

Receive circuitry 510 may further include switching circuitry 512 (e.g.,receiver matching and switching circuitry) for connecting receiveantenna 518 to the power conversion circuitry 506 or alternatively fordisconnecting the power conversion circuitry 506. Disconnecting receiveantenna 518 from power conversion circuitry 506 not only suspendscharging of device 550, but also changes the “load” as “seen” by thetransmitter 404 (FIG. 2).

As disclosed above, transmitter 404 includes load sensing circuit 416that may detect fluctuations in the bias current provided to transmitterdriver circuit 424. Accordingly, transmitter 404 has a mechanism fordetermining when receivers are present in the transmitter's near-field.

When multiple receivers 508 are present in a transmitter's near-field,it may be desirable to time-multiplex the loading and unloading of oneor more receivers to enable other receivers to more efficiently coupleto the transmitter 404. A receiver 508 may also be cloaked in order toeliminate coupling to other nearby receivers or to reduce loading onnearby transmitters. This “unloading” of a receiver is also known hereinas a “cloaking.” Furthermore, this switching between unloading andloading controlled by receiver 508 and detected by transmitter 404 mayprovide a communication mechanism from receiver 508 to transmitter 404as is explained more fully below. Additionally, a protocol may beassociated with the switching that enables the sending of a message fromreceiver 508 to transmitter 404. By way of example, a switching speedmay be on the order of 100 μsec.

In an exemplary embodiment, communication between the transmitter 404and the receiver 508 refers to a device sensing and charging controlmechanism, rather than conventional two-way communication (i.e., in bandsignaling using the coupling field). In other words, the transmitter 404may use on/off keying of the transmitted signal to adjust whether energyis available in the near-field. The receiver may interpret these changesin energy as a message from the transmitter 404. From the receiver side,the receiver 508 may use tuning and de-tuning of the receive antenna 518to adjust how much power is being accepted from the field. In somecases, the tuning and de-tuning may be accomplished via the switchingcircuitry 512. The transmitter 404 may detect this difference in powerused from the field and interpret these changes as a message from thereceiver 508. It is noted that other forms of modulation of the transmitpower and the load behavior may be utilized.

Receive circuitry 510 may further include signaling detector and beaconcircuitry 514 used to identify received energy fluctuations that maycorrespond to informational signaling from the transmitter to thereceiver. Furthermore, signaling and beacon circuitry 514 may also beused to detect the transmission of a reduced RF signal energy (i.e., abeacon signal) and to rectify the reduced RF signal energy into anominal power for awakening either un-powered or power-depleted circuitswithin receive circuitry 510 in order to configure receive circuitry 510for wireless charging.

Receive circuitry 510 further includes processor 516 for coordinatingthe processes of receiver 508 described herein including the control ofswitching circuitry 512 described herein. Cloaking of receiver 508 mayalso occur upon the occurrence of other events including detection of anexternal wired charging source (e.g., wall/USB power) providing chargingpower to device 550. Processor 516, in addition to controlling thecloaking of the receiver, may also monitor beacon circuitry 514 todetermine a beacon state and extract messages sent from the transmitter404. Processor 516 may also adjust the DC-to-DC converter 522 forimproved performance.

FIG. 6 is a schematic diagram of a portion of transmit circuitry 600that may be used in the transmit circuitry 406 of FIG. 4. The transmitcircuitry 600 may include a driver circuit 624 as described above inFIG. 4. As described above, the driver circuit 624 may be a switchingamplifier that may be configured to receive a square wave and output asine wave to be provided to the transmit circuit 650. In some cases thedriver circuit 624 may be referred to as an amplifier circuit. Thedriver circuit 624 is shown as a class E amplifier (e.g., comprising atransistor 604, inductors 606, 608, and a capacitor 610), however, anysuitable driver circuit 624 may be used in accordance with embodimentsof the invention. The driver circuit 624 may be driven by an inputsignal 602 from an oscillator 423 as shown in FIG. 4. The driver circuit624 may also be provided with a drive voltage V_(D) that is configuredto control the maximum power that may be delivered through a transmitcircuit 650. To eliminate or reduce harmonics, the transmit circuitry600 may include a filter circuit 626. The filter circuit 626 may be athree pole (capacitor 634, inductor 632, and capacitor 636) low passfilter circuit 626.

The signal output by the filter circuit 626 may be provided to atransmit circuit 650 comprising an antenna 614. The transmit circuit 650may include a series resonant circuit having a capacitance 620 andinductance (e.g., that may be due to the inductance or capacitance ofthe antenna or to an additional capacitor component) that may resonateat a frequency of the filtered signal provided by the driver circuit624. The load of the transmit circuit 650 may be represented by thevariable resistor 622. The load may be a function of a wireless powerreceiver 508 that is positioned to receive power from the transmitcircuit 650.

When multiple transmitters are within out-of-band communication range ofa receiver, it is important to establish communications with thetransmitter best suited for transferring wireless power to the receiver.Out-of-band communications between the transmitter and the receiver canbe carried out over a separate communication channel from the wirelesspower transfer field, as described below. FIG. 7A is a functional blockdiagram depicting the case where a receiver 208 is located in proximityto multiple transmitters 204, 204 a, and 204 b. As shown, receiver 208is located so as to receive wireless power from transmitter 204 viafield 205. However, receiver 208 is capable of establishing anout-of-band communication channel 219 with transmitters 204, 204 a, and204 b. Thus, if receiver 208 establishes channel 219 with transmitter204 a or 204 b, any subsequent communications related to power transferwould be irrelevant. This situation may be referred to herein as amisconnection or cross connection.

FIG. 7B is a block diagram of another example of cross connection in asystem comprising two power transmitter units (PTU#1 and PTU#2) and fourpower receiver units (PRU#1, PRU#2, PRU#3, PRU#4). For example, a mediumrange communication system, e.g., Bluetooth Low Energy (BLE), can have arange of 10-50 meters potentially resulting in a condition in which apower receiver unit can connect to the wrong power transmitter unit. Asshown in FIG. 7B, PRU#1 has correctly connected to PTU#1, and PRU#4 hascorrectly connected to PTU#2. However, PRU#2 has incorrectly connected(or cross connected) to non-co-located PTU#2 and PRU#3 has incorrectlyconnected (or cross connected) to non-co-located PTU#1. As shown in FIG.7B, PRU#2 may have a communication connection to PTU#2 while having awireless power connection to PTU#1, and PRU#3 may have a communicationconnection to PTU#1 while having a wireless power connection to PTU#2.

Wireless charging systems are expected to operate in variousillustrative environments, some with multiple power transmission unitsand multiple power receiver units in which the problem of crossconnections can arise. For example, a “solo” environment can comprise asingle power transmission unit and a single power receiver unit, so nocross connection can result. As another example, a “residential”environment can comprise multiple (e.g., two) power transmission unitsspaced (for example, 10 meters) apart from one another and operatedconcurrently with one another. As another example, a “coffee shop”environment can comprise multiple (e.g., 10) power transmission unitsspaced (for example, 2 meters) from one another. Thus, there can bemultiple power transmission units that are “visible” or detectable bymost power receiver units in the vicinity, and a number (e.g., 5) ofthese power transmission units can be active at any given time. Asanother example, a “stadium” environment can comprise multiple (e.g.,more than 1000) power transmission units spaced (for example, one meter)apart from one another (e.g., 1 per square meter). Thus, there can bemany (e.g., 300) power transmission units “visible” or detectable bypower receiver units within a distance range (for example, 10 meters).

Attempts to prevent incorrect corrections or cross connections may fail,for example, by incorrectly rejecting a co-located power receiving unit(false rejection), or by incorrectly allowing a cross-connected powerreceiving unit to remain connected (false acceptance). For falserejection, a chargeable device on a correct wireless charger isincorrectly rejected, and can be caused by excessive Z separation or bysystem instability. Potential results of such false rejections include,but are not limited to, long period of rejection (e.g., minutes) untilthe device is re-accepted, and system trip (e.g., shutdown of some orall functionality of the wireless charger) due to apparent measurementof the transmitter transmitting too much power without seeing acorresponding increase in received power. For false acceptance, achargeable device on another wireless charger is incorrectly accepted bythe wireless charger as its own. Such failures can be caused by goodmatching across wireless chargers or by coincident timing (e.g., powerbeing restored to multiple wireless chargers at the same time).

Out-of-band communication (e.g., an advertisement) may be implementedthrough the use of any wireless communication protocol having a range ofimplementation (e.g., a proprietary communication protocol, acommunication protocol established by a standards organization likeIEEE, etc., IrDA, Wireless USB, Z-Wave, ZigBee, Bluetooth Low Energy(BLE), and/or the like). Having multiple power transmitting units withinthis range can contribute to the problem of cross connection.

FIG. 7C is a block diagram of a wireless power system 700 capable ofout-of-band communications that may incorporate the transmit circuitry406 of FIG. 4 and the receive circuitry 510 of FIG. 5. The wirelesspower system 700 may comprise a wireless charger 702 (e.g., a powertransmitter unit) and a chargeable device 704 (e.g., a power receiverunit).

The wireless charger 702 may comprise a wireless power antenna 714 and awireless power transmitter 710 coupled to the wireless power antenna 714and configured to generate a wireless charging field (e.g., a magneticfield) in at least one charging region (e.g., one, two, three, or morecharging regions). The wireless charging field can comprise a pluralityof power signals. The wireless charger 702 can further comprise acommunication antenna 724 and a transceiver 720 (e.g., an out-of-bandcommunication transceiver) coupled to the communication antenna 724 andconfigured to communicate with the chargeable device via thecommunication antenna 724. The wireless charger 702 can further comprisea controller 730 configured to facilitate avoidance of cross connectionof the chargeable device 704 with the wireless charger 702 and at leastone other wireless charger (e.g., to prevent cross connection, to reducea probability of cross connection, to terminate a cross connection). Insuch cross connection, the chargeable device 704 would receive powerfrom one of the wireless charger 702 or the at least one other wirelesscharger (not shown) while the chargeable device 704 is communicatingwith the other of the wireless charger 702 or the at least one otherwireless charger (not shown).

In an embodiment, the transmit antenna 714 may be similar to thetransmit antenna 414 of FIG. 4, and the wireless power transmitter 710of the wireless charger 702 may be similar to and/or include the samefunctionality as the transmit circuitry 406 of FIG. 4. In an embodiment,the wireless power transmitter 710 may be configured to transmit powerwirelessly to charge the chargeable device 704 (e.g., to the wirelesspower receiver 715 of the chargeable device 704) by generating thewireless charging field in the at least one charging region.

The chargeable device 704 may comprise a wireless power antenna 718configured to receive power from a wireless charger (e.g., the wirelesscharger 702) and a wireless power receiver 715 coupled to the wirelesspower antenna 718. The chargeable device 704 can further comprise acommunication antenna 728 and a transceiver 725 (e.g., an out-of-bandcommunication transceiver) coupled to the communication antenna 728 andconfigured to communication with the wireless charger (e.g., wirelesscharger 702) via the communication antenna 728. The chargeable device704 can further comprise a controller 735 configured to facilitateavoidance of cross connection of the chargeable device 704 with thewireless charger 702 and at least one other wireless charger (e.g., toprevent cross connection, to reduce a probability of cross connection,to terminate a cross connection). For example, as described in moredetail below, the controller 735 can be configured to generate a loadpulse configured to be received by the wireless charger (e.g., wirelesscharger 702).

In an embodiment, the chargeable device 704 may be similar to thechargeable device 550 of FIG. 5, and the wireless power receiver 715 maybe similar to and/or include the same functionality as the receivecircuitry 510 of FIG. 5. Likewise, the wireless power receiver 715 maybe coupled to a receive antenna 718. The receive antenna 718 may besimilar to the receive antenna 518 of FIG. 5.

As shown in FIG. 7C, the out-of-band communication transceiver 720 maybe coupled to antenna 724 and the out-of-band communication transceiver725 may be coupled to antenna 728. In an embodiment, the out-of-bandcommunication transceivers 720 and 725, via antennas 724 and 728, may beused to establish a connection between the wireless charger 702 and thechargeable device 704 such that the chargeable device 704 can receivepower wirelessly from the wireless charger 702 in order to charge itsbattery or similar device. The out-of-band communication (e.g., aninitial notification of the placement of the device to be charged, anadvertisement, or other communications relating to management of thewireless power session) may be implemented through the use of anywireless communication protocol (e.g., a proprietary communicationprotocol, a communication protocol established by a standardsorganization like IEEE, etc.). For example, IrDA, Wireless USB, Z-Wave,ZigBee, Bluetooth Low Energy (BLE), and/or the like may be used.

To better understand the resolution techniques disclosed herein, it ishelpful to understand an exemplary method for establishing anout-of-band communication channel. FIG. 8 is a timing and signal flowdiagram of an example of communications between a wireless charger and achargeable device, such as the wireless charger 702 (e.g., powertransmitter unit) and the chargeable device 704 (e.g., power receiverunit), to establish a connection between the wireless charger and thechargeable device. The wireless charger 702 may transmit a power pulse802 (e.g., a beacon signal), where the power pulse 802 can be used tosupply power to a chargeable device, like chargeable device 704, tocharge the chargeable device (or at least to provide a sufficient levelof power such that the chargeable device 704 may power its out-of-bandcommunication transceiver 725 for sending initialization messages to thewireless charger 702). The wireless charger 702 may transmit the powerpulse 802 in order to detect a chargeable device 704. As illustrated inFIG. 8, the power pulse 802 was transmitted, but no chargeable device704 was in range of the power pulse 802. The wireless charger 702 maywait a period of time before transmitting another power pulse 804. Forexample, the wireless charger 702 may wait 1 second between pulses. Upontransmitting the power pulse 802 and/or 804, the wireless charger 702may start a general connection establishment procedure. As illustratedin FIG. 8, the power pulse 804 was transmitted and in range of thechargeable device 704.

Once the wireless charger 702 detects a load on the power pulse 804, thewireless charger 702 begins scanning for a broadcast from a device, likethe chargeable device 704. In this manner, the wireless charger 702 mayconserve power by only scanning for a broadcast once it detects a loadon a power pulse. In an embodiment, the power pulse 804 causes thechargeable device 704 to generate a broadcast (e.g., a processor of thechargeable device 704 may generate the broadcast). As an example, thebroadcast 806 may be message(s) transmitted over Bluetooth Low Energychannels. The chargeable device 704 may transmit the broadcast 806 withthe wireless charger 702 as the intended recipient. If the broadcast 806does not reach the wireless charger 702 (as depicted in FIG. 8), thenthe chargeable device 704 may generate and transmit another broadcast808. For example, the chargeable device 704 may wait 20 ms beforesending another broadcast 808. If a connection is not established withina certain time frame, such as 10 seconds, the chargeable device 704 mayexit a connectable mode and stop any charging that may have started. Inthis manner, the chargeable device 704 may conserve power by onlygenerating and transmitting a broadcast 806 and/or 808 once it receivesa power pulse 802 and/or 804 from the wireless charger 702.

Note that there are numerous situations in which a misconnection (e.g.,cross connection) may occur. For example, another device besideschargeable device 704, or an object in the vicinity of the wirelesscharger 702, may cause the wireless charger 702 to detect a load andbegin scanning for a broadcast. As another example, some chargers maycontinually scan for a broadcast independent of the timing of powerpulses 802 and 804. As yet another example, some chargeable devices maycontinually broadcast independent of the timing of power pulses 802 and804. As yet another example, a wireless charger may respond to abroadcast before the charger which originated a power pulse, preemptingthe initialization of communications. Consequently, in these and othersituations the wireless charger 702 may inadvertently establishcommunications with a chargeable device located outside an effectivecharging region, resulting in a misconnection or cross connection.

Once the wireless charger 702 receives the broadcast 808, the wirelesscharger may transmit a connection request 812 to the chargeable device704. If the chargeable device 704 accepts the connection request 812,then a connection 814 is established between the wireless charger 702and the chargeable device 704.

Note that during the connection process illustrated in FIG. 8, thewireless charger 702 may continue to transmit power 810, such as via thepower pulse 802 and/or 804, in order to charge the chargeable device704. In some aspects, the chargeable device 704 may be in a chargerpowered mode, and the power 810 would allow the chargeable device 704 toremain active in order to establish a connection with the wirelesscharger 702. Once the wireless charger 702 determines that a connectioncannot be established, that the chargeable device 704 is now in aself-powered mode, and/or that the chargeable device 704 otherwise doesnot need the power transmitted from the wireless charger 702, then thewireless charger 702 may stop transmitting the power 810.

If a connection is lost at any point, the chargeable device 704 mayattempt to reconnect with the wireless charger 702. Alternatively, thechargeable device 704 may wait until it receives another power pulse 802and/or 804 from the wireless charger 702.

Several methods disclosed herein may be used to assist in the correctconnection of out-of-band signaling between a wireless charger 702 and achargeable device 704, and/or ascertain whether an out-of-bandcommunication channel has been improperly established between thewireless charger 702 and the chargeable device 704 (e.g., amisconnection or a cross connection). These methods are referred toherein as resolution methods. Some of these resolution methods do notnecessarily guarantee an out-of-band communication channel has beenestablished between the optimal transmitter and receiver. Instead, somemethods tend to inferentially support or undermine the propriety of theestablished communication channel. Accordingly, one or more of theseresolutions methods may be used alone or in combination with one anotherin a wireless power transfer system to facilitate avoidance of crossconnection (e.g., to prevent cross connection, to reduce a probabilityof cross connection, to terminate a cross connection). Further, theoutput of these resolution methods may be compared against a thresholdfor that particular method and/or combined with other methods disclosedherein. The outputs of these methods may be weighted and used in aprobabilistic or fuzzy logic type model to evaluate whether there hasbeen a misconnection and out-of-band communication should attempt toreconnect.

The resolution methods may be carried out by a controller (e.g.,controller 415 of FIG. 4, processor 516 of FIG. 5, controllers 730, 735of FIG. 7). In one embodiment, the resolution method(s) may be evaluatedby a transmitter-side controller (e.g., wireless charger controller 730)with receiver-side measurements transmitted over the out-of-bandcommunication channel. In another embodiment, the resolution methods maybe evaluated either transmitter-side or receiver-side, with theresulting output(s) transmitted via the out-of-band communicationchannel to the transmitter (or receiver). Further, upon identifying amisconnection (e.g., cross connection) but before dropping theout-of-band communication channel, the local controller (e.g.,controller 730 or 735) may notify the remote controller (e.g., the otherof controller 730 or 735) of the misconnection. In certain embodiments,the controller (e.g., controller 730 or 735) can provide additional timeto allow the connection to be made to resolve cross connections, e.g.,adding to the total time between placement of the chargeable device 704to resolving any cross connections. In particular, congestedenvironments with many wireless chargers and many chargeable devices cantake a significant amount of time to resolve any cross connections.

A “lost power” process can use power measurements (e.g., AC or DC)compared to reported power at the chargeable device 704 to calculate anamount of “lost” power, with the intent to shut down power to thewireless charger 702 when too much power is unaccounted for, therebyhelping to prevent heating of metallic objects placed on the wirelesscharger during operation. To accurately measure lost power, an accuratecount of the number of devices receiving power is desirable, but such anaccurate count may not be available when cross connections occur. Thus,cross connections can result in unexpected shutdowns if a lost poweralgorithm is utilized, thereby degrading the user experience. By leaving“off” any chargeable devices suspected of being cross connected tomultiple power chargers, the amount of power drawn by the chargeabledevice 704 and the odds of a power trip due to lost power are reduced.However, since the chargeable device 704 will not be charging under suchcircumstances, the user experience may suffer. Thus, in certainembodiments, the resolution techniques described herein can improve theuser experience.

Saturation test

In certain embodiments, a wireless power system uses a data link tocontrol the power transmitted by the wireless charger 702 to thechargeable device 704. For example, an out-of-band communication channelas described herein with regard to FIG. 8 can be used to initiate thedata link (e.g., the connection 814). The data link can be used by thechargeable device 704 to request more power from the wireless charger702 when a voltage (e.g., a sensed output voltage of the receivecircuitry 510) of the chargeable device 704 indicates that the amount ofpower being transferred is below a predetermined level indicative ofpower transfer that is too low. In addition, the data link can be usedby the chargeable device 704 to request less power from the wirelesscharger 702 when a voltage (e.g., a sensed output voltage of the receivecircuitry 510) is above a predetermined level indicative of powertransfer that is too high. During normal operations, such use of thedata link can be used to optimize the power transfer from the wirelesscharger 702 to the one or more chargeable devices 704, so that all thechargeable devices 704 receive an acceptable amount of power transfer.

However, during cross connection, the behavior of the wireless powersystem utilizing the data link can be nonsensical or paradoxical. Forexample, if a chargeable device 704 is cross connected (e.g., receivingpower from one wireless charger 702 but communicating with anotherwireless charger 702), the chargeable device 704 will not detect achange in the transmitted power when it requests a change of transmittedpower, since the request is not being communicated to the wirelesscharger 702 providing power to the chargeable device 704, but to anotherwireless charger 702. Such a cross connection condition can lead to asaturation of the power level of the wireless charger 702 receiving therequests. As such, in accordance with an aspect of an embodiment, if acontroller (e.g., a controller 730 of the wireless charger 702, acontroller 735 of the chargeable device 704) determines that a requestfor a change in power is not matched by an actual change in power, thecontroller may determine that a cross-connection may potentially bepresent. Furthermore, for example, a wireless charger 702 receivingrequests for more power from a cross connected chargeable device 704could end up being saturated at its maximum power, while the chargeabledevice 704 is detecting little power available (e.g., resulting in thechargeable device 704 requesting more power). Alternatively, a wirelesscharger 702 receiving requests for less power from a cross connectedchargeable device 704 could end up being saturated at its minimum power,while the chargeable device 704 is detecting a high amount of poweravailable (e.g., resulting in the chargeable device 704 requesting lesspower).

FIG. 9 is a flow diagram of an example first resolution method 900 offacilitating avoidance of cross connection of a chargeable device 704 incommunication with a wireless charger 702 in accordance with certainembodiments described herein. In an operational block 910, a transmittedpower level of a wireless charger 702 is detected. In an operationalblock 920, the detected transmitted power level can be compared to atleast one predetermined level indicative of at least one saturationcondition. For example, the detected transmitted power level can becompared to a first predetermined level indicative of a maximum powersaturation condition. The maximum power saturation condition maycorrespond to a condition in which the transmitted power is at or abovea first power level. The first power level may correspond to a maximumallowable level. The maximum allowable level may be some upper limitbased on one or more characteristics or protocols for operating thewireless charger 702 (e.g., based on either limits according toaccommodating different types of chargeable devices or for protection ofcertain components of the wireless charger 702). In some cases thedetected transmitted power level can be compared to a secondpredetermined level indicative of a minimum power saturation condition.The minimum power saturation condition may correspond to a condition inwhich the transmitted power is at or below a second power level. Thesecond power level may correspond to a minimum allowable level. Theminimum allowable level may be some lower limit based on one or morecharacteristics or protocols for operating the wireless charger 702. Inan operational block 930, the wireless charger 702 can initiate (e.g.,force) a disconnection of a communication link between the wirelesscharger 702 and the chargeable device 704 based at least in part onwhether the at least one saturation condition exists, thus ending thecross connection. For example, the wireless charger 702 can initiate(e.g., force) a disconnection of the wireless charger 702 from thechargeable device 704 if the detected transmitted power level is at orabove the first predetermined level or can initiate (e.g., force) adisconnection if the detected transmitted power level is at or below thesecond predetermined level. In certain embodiments, a request for poweradjustment (e.g., a requested change of the transmitted power) from thechargeable device 704 can be detected. For example, a requested changeof the transmitted power can correspond to at least one of: a requestfor an increased level of power when the at least one saturationcondition is indicative of a maximum allowable transmitter power level;or a request for a decreased level of power when the at least onesaturation condition is indicative of a minimum allowable transmitterpower level. The request for power adjustment can be compared to the atleast one predetermined level, and a disconnection of the wirelesscharger 702 from the chargeable device 704 can be initiated based onthis comparison (e.g., based on whether the requested power adjustmentwould place the transmitted power level above a maximum power saturationcondition or below a minimum power saturation condition).

In certain embodiments, detecting the transmitted power level, comparingthe detected transmitted power level, and initiating the disconnectionare performed by the wireless charger 702 (e.g., by a controller of thewireless charger 702). In other certain embodiments, detecting thetransmitted power level, comparing the detected transmitted power level,and initiating the disconnection are performed by the chargeable device704 (e.g., by a controller 735 of the chargeable device 704). In stillother certain embodiments, at least one of detecting the transmittedpower level, comparing the detected transmitted power level, andinitiating the disconnection is performed by the wireless charger 702(e.g., by a controller 730 of the wireless charger 702) and at least oneother of detecting the transmitted power level, comparing the detectedtransmitted power level, and initiating the disconnection is performedby the chargeable device 704 (e.g., by a controller of the chargeabledevice 704).

In certain embodiments, to avoid disconnecting during inadvertenttransient changes in power, the wireless charger 702 does not initiatethe disconnection until the saturation condition persists for apredetermined amount of time (e.g., one second, two seconds, or more).For example, the wireless power system 700 (e.g., a controller of thewireless charger 702; a controller of the chargeable device 704) can beconfigured to detect whether the at least one saturation conditionexists for the predetermined period of time, and to perform initiatingthe disconnection after detecting that the at least one saturationcondition persists for the predetermined period of time.

In certain embodiments, the wireless power system 700 (e.g., acontroller 730 of the wireless charger 702; a controller 735 of thechargeable device 704) is configured to distinguish between a crossconnection condition and non-cross connection conditions in which the atleast one saturation condition exists, and is configured to not initiatea disconnection if a non-cross connection condition exists. For example,the wireless power system 700 (e.g., a controller 730 of the wirelesscharger 702; a controller 735 of the chargeable device 704) can beconfigured to detect a condition in which the wireless charger 702 andthe chargeable device 704 are separated by a finite distance (e.g., by apad of paper sandwiched between the wireless charger 702 and thechargeable device 704) and/or a condition in which the power requestedby the chargeable device 704 exceeds the maximum power the wirelesscharger 702 can provide. Due to such separation or such excessive powerrequests, the wireless charger 702 may be saturated at maximum powerwhile the chargeable device 704 is at a relatively low power, eventhough there is no cross connection. Such a case can be detected sincethe voltage of the chargeable device 704 will still rise as the wirelesscharger 702 increases power due to requests for increased power from thechargeable device 704, although the voltage of the chargeable device 704may not achieve an adequate, desired, or ideal level.

In certain embodiments, the wireless charger 702 can make a furtherdetermination as to whether a chargeable device 704 is cross-connectedby causing an intentional and predetermined magnitude change of thetransmitted power from the wireless charger 702 for a predeterminedperiod of time. This intentional and predetermined magnitude change forthe predetermined period of time can be requested by the wirelesscharger 702 or by the chargeable device 704 (e.g., by the controller 730of the wireless charger 702; by the controller 735 of the chargeabledevice 704), and can be performed by the wireless charger 702 (e.g., bythe controller of the wireless charger 702). For example, if achargeable device 704 is suspected of being cross-connected due to theabove saturation test of operational block 920 (or due to other testsdescribed herein), then the wireless charger 702 can intentionallyperform a transient change in the transmitted power and the wirelesspower system 700 (e.g., a controller 730 of the wireless charger 702; acontroller 735 of the chargeable device 704) can compare the detectedchange of the detected transmitted power to the magnitude of theintentional change to determine whether the chargeable device 704detects this intentional change in the transmitted power. If thechargeable device 704 does detect this intentional change in thetransmitted power, it is very likely that the chargeable device 704 isin communication with the wireless charger 702 (e.g., the chargeabledevice 704 is positioned on the wireless charger 702) and that thechargeable device 704 is not experiencing cross connection. Likewise, ifthe chargeable device 704 does not detect the intentional change in thetransmitted power (e.g., detects no change or detects a change thatdiffers by at least a predetermined amount from the change), it is verylikely that the chargeable device 704 is not in communication with thewireless charger 702 (e.g., the chargeable device 704 is not positionedon the wireless charger 702) and the chargeable device 704 may beexperiencing cross connection.

The wireless power system 700 (e.g., a controller 730 of the wirelesscharger 702; a controller 735 of the chargeable device 704) can, incertain embodiments, make intelligent decisions about how to select(e.g., tailor) the predetermined magnitude and the period of time of thechange of the transmitted power to avoid adversely affecting thetransfer of power from the wireless charger 702 to chargeable devices704 properly connected to the wireless charger 702. For example, if awireless charger 702 has three chargeable devices 704 within its chargearea, and two of these chargeable devices 704 are properly connected tothe wireless charger 702 and charging, but a third chargeable device 704is suspected of being cross connected, the wireless charger 702 canselectively alter the transmitted power (e.g., to increase thetransmitted power or to decrease the transmitted power) so that the twochargeable devices 704 that are operating correctly are not adverselyaffected. In the above example, if the two chargeable devices 704 werereporting that they were receiving power that resulted in a voltage thatwas barely sufficient to charge, the wireless charger 702 could increasethe transmitted power transiently (e.g., for a predetermined period oftime). If the two chargeable devices 704 were reporting that they werenear their maximum voltage limit, then the wireless charger 702 coulddecrease the transmitted power transiently (e.g., for a predeterminedperiod of time). If the two chargeable devices 704 were reporting thatthey were near their maximum and minimum voltage limits respectively,the wireless charger 702 could elect to not make a transient change inthe transmitted power, so as to avoid interrupting power to either ofthe two connected chargeable devices 704. In certain such embodiments,the wireless charger 702 could rely on other tests as described herein.

Randomized Transmitter Turn-On

Under certain circumstances, during initial turn-on of the wirelesspower system 700, multiple wireless chargers 702 may turn on at or nearthe same time as one another, with multiple chargeable devices 704 inproximity to the wireless chargers 702 (e.g., each chargeable device 704positioned on one of the wireless chargers 702), ready to be charged.For example, an initial power-on of a branch circuit supplying themultiple wireless chargers 702 with power could cause this condition tooccur. If all the wireless chargers 702 are turned on at or near thesame time, then the multiple chargeable devices 704 will detect powerbeing applied at or near the same time, resulting in the multiplechargeable devices 704 potentially all trying to connect to acorresponding wireless charger 702 at or near the same time. During sucha case, a wireless charger 702 may have difficulty determining whichchargeable device 704 is within its own charging area.

FIG. 10 is a flow diagram of an example of a second resolution method1000 of facilitating avoidance of cross connection of a chargeabledevice 704 in communication with a wireless charger 702 in accordancewith certain embodiments described herein. In an operational block 1010of the method 1000, for each wireless charger 702 of a plurality ofwireless chargers 702 operatively coupled to a common power circuit(e.g., a common branch circuit), a time period between (i) power beingprovided to the wireless charger 702 via the common power circuit and(ii) the wireless charger 702 being turned on (e.g., wirelesslytransferring power to one or more chargeable devices 704) is set to arandom value for the wireless charger 702. This operational block 1010can be referred to as randomizing the turn-on timing of the wirelesschargers 702. The random value can be selected by a controller 730 ofthe wireless charger 702 and can be selected from a predetermined rangeof values (e.g., between zero and one second). While the example method1000 of FIG. 10 is described in conjunction with an exampleconfiguration having a plurality of wireless chargers 702 operativelycoupled to a common power circuit, certain other embodiments describedherein are utilized with other configurations that are not constrainedin this manner. In an operational block 1020 of the method 1000, uponpower being provided to the common power circuit, each wireless charger702 of the plurality of the wireless chargers 702 is turned on after itscorresponding random time period has elapsed.

By randomizing the turn-on timing of the wireless chargers 702 asdescribed above, the chargeable devices 704 will not all attempt toconnect their data links to the wireless chargers 702 at or near thesame time. For example, in certain embodiments, in accordance with FIG.8, since the chargeable device 704 sends a connection request broadcast808 subsequent to receiving a power pulse 804, the random turn-on timeswill cause variation in when the chargeable devices 704 attempt toconnect their data links. Random turn-on timing increases the odds thata given wireless charger 702 will power up at a moment in time that isunique to the wireless charger 702, and thus the one or more chargeabledevices 704 within the charging area of the wireless charger 702 willattempt to connect at a unique moment of time. By detecting only thosechargeable devices 704 within its charging area that are attempting toconnect after the wireless charger 702 applies power, the incidence ofcross connection can be greatly reduced.

Available Charge Area Versus Size of Chargeable Device

A wireless charger 702 can have or define a charging region in which itcan effectively transfer power to one or more chargeable devices 704,and each chargeable device 704 can have a corresponding size. Thecharging region can have a predetermined charging area, and as eachchargeable device 704 is placed within the charging area of the wirelesscharger 702, the amount of the charging area that is free to acceptadditional chargeable devices 704 decreases, until the charging area canno longer reasonably accommodate additional chargeable devices 704.Thus, the charging area can only reasonably accommodate a finite numberof chargeable devices 704 concurrently. If the amount of the chargingarea of a first wireless charger 702 that is free to accept additionalchargeable devices 704 is less than the area of an additional chargeabledevice 704 (e.g., the finite number of chargeable devices 704 is alreadyconnected to the first wireless charger 702), and an additionalchargeable device 704 attempts to connect to the first wireless charger702, then this additional chargeable device 704 can be considered tohave a high probability that it is actually positioned on another secondwireless charger 702, such that its connection to the first wirelesscharger 702 would result in a cross-connection condition.

FIG. 11 is a flow diagram of an example of a third resolution method1100 of facilitating avoidance of cross connection of a chargeabledevice 704 in communication with a wireless charger 702 in accordancewith certain embodiments described herein. In an operational block 1110,a charging area of a wireless charger 702 is determined. For example, acontroller 730 of the wireless charger 702 can have access to a memory(not shown) that specifies the charging area of the wireless charger702. In an operational block 1120, for each chargeable device 704 thatattempts to connect to the wireless charger 702, the area of thechargeable device 704 can be compared to the free amount of the chargingarea (e.g., the amount of the charging area that is free to accept thechargeable device 704). For example, upon receiving a request from achargeable device 704 to connect to the wireless charger 702, thecontroller 730 can compare the area of the chargeable device 704 to theamount of the charging area that is free to accept the chargeable device704.

In an operational block 1130, the connection between the chargeabledevice 704 and the wireless charger 702 can be accepted or rejected inresponse at least in part to the comparison. For example, if the area ofthe chargeable device 704 is less than or equal to the amount of thecharging area that is free to accept the chargeable device 704, then thecontroller 730 can allow the chargeable device 704 to connect to thewireless charger 702. For another example, if the area of the chargeabledevice 704 is greater than the amount of the charging area that is freeto accept the chargeable device 704, then the controller 730 can reject(e.g., refuse to allow) the chargeable device 704 to connect to thewireless charger 702 or complete other operations or tests to determinewhether there is a cross-connection issue. In an operational block 1140,in response to accepting a connection between a chargeable device 704and the wireless charger 702 or in response to termination of aconnection between a chargeable device 704 and the wireless charger 702,the amount of the charging area that is free to accept a chargeabledevice 704 can be revised. For example, in response to accepting aconnection between a chargeable device 704 and the wireless charger 702,the controller 730 can recalculate the amount of the charging area thatis free to accept a chargeable device 704 by subtracting the area of thechargeable device 704 from the previous value of the free amount of thecharging area. For another example, in response to terminating aconnection between a chargeable device 704 and the wireless charger 702,the controller 730 can recalculate the amount of the charging area thatis free to accept a chargeable device 704 by adding the area of thechargeable device 704 from the previous value of the free amount of thecharging area. Charging area may not be added if there is some level ofuncertainty over whether the device is cross-connected, based onmeasurements of other parameters, as specified herein.

Time Windows on Data Connection

When power is first applied to a wireless charger 702, a chargeabledevice 704 that detects power from the wireless charger 702 can takesome amount of time (e.g., 50 ms) to start up and enable the dataconnection between the chargeable device 704 and the wireless charger702 (for example, particularly in scenarios where a battery of thechargeable device 704 is completely depleted). A chargeable device 704that is being powered from a battery can also intentionally wait someamount of time from the moment that it first detects power from awireless charger 702 to the moment the chargeable device 704 enables itsdata connection (e.g., 50 ms) with the wireless charger 702. In bothcases, the chargeable device 704 can be configured to enable its dataconnection to a wireless charger 702 within a predetermined maximum timeperiod (e.g., 70 ms). Thus, in certain circumstances, there can be atime window (e.g., between 50 ms and 70 ms) during which a chargeabledevice 704 positioned within a charging region of a wireless charger 702(e.g., positioned on a charging pad) will enable the data connectionbetween the chargeable device 704 and the wireless charger 702 afterpower is applied to the wireless charger 702. The wireless charger 702can utilize this time window as an acceptance time window by acceptingdata connections that are requested within the time window and byrejecting data connections that are requested outside this time window.Chargeable devices 704 that are requesting data connections outside theacceptance time window of a wireless charger 702 can be assumed to bedetecting power from a different wireless charger 702, and such dataconnections can be rejected to avoid cross connection.

FIG. 12 is a flow diagram of an example of a fourth resolution method1200 of facilitating avoidance of cross connection of a chargeabledevice 704 in communication with a wireless charger 702 in accordancewith certain embodiments described herein. In an operational block 1210,an acceptance time window is defined for the wireless charger 702. Forexample, a controller 730 of the wireless charger 702 can have access toa memory (not shown) that specifies the acceptance time window of thewireless charger 702. The acceptance time window can occur after achargeable device 704 positioned within a charging region of thewireless charger 702 detects power from the wireless charger 702. Theacceptance time window can have a first endpoint at a firstpredetermined amount of time after power is applied to the wirelesscharger 702 and a second endpoint at a second predetermined amount oftime after power is applied to the wireless charger 702. For example,the first predetermined amount of time can correspond to a minimumexpected delay between detecting power from the wireless charger 702 andenabling a data connection between the chargeable device 704 and thewireless charger 702 (e.g., 50 ms). In certain embodiments, the expecteddelay may start from a point when the wireless charger 702 transmits apower pulse 804 as described above with reference to FIG. 8. In otherembodiments, the expected delay may start from some other period, suchas, for example when the wireless charger 702 detects an indication(e.g., a change in impedance or other characteristic) that a chargeabledevice 704 may have been positioned within a charging area of thewireless charger 702 as is further described below. The secondpredetermined amount of time can correspond to a maximum expected delaybetween detecting power from the wireless charger 702 and enabling adata connection between the chargeable device 704 and the wirelesscharger 702 (e.g., 70 ms). In an operational block 1220, the wirelesscharger 702 receives a request to enable a data connection from achargeable device 704. In an operational block 1230, the wirelesscharger 702 determines whether the request occurs within the acceptancetime window. For example, upon receiving a request from a chargeabledevice 704 to connect to the wireless charger 702, the controller 730can compare the timing of the request to the acceptance time window. Inan operational block 1240, the data connection can be accepted orrejected in response to whether the request occurs within the acceptancetime window or not. For example, if the request occurs during theacceptance time window, the data connection can be accepted, and if therequest does not occur during the acceptance time window, the dataconnection can be rejected.

Time Windows on Data Connection with Device Detection

In certain embodiments, the wireless charger 702 can comprise a sensoror other means for detecting whether a chargeable device 704 has beenpositioned within the charging region of the wireless charger 702. Forexample, the wireless charger 702 can comprise a sensor configured todetect changes of the transmit resonator impedance (for example, theload sensing circuit 416 of FIG. 4 may be configured to detect similarchanges in certain embodiments). The wireless charger 702 may detect aquestionable indication that a chargeable device 704 has been placed inthe charging region. For example, a detected impedance shift may besmaller than the impedance shift expected to occur from a chargeabledevice 704 being placed in the charging region. In certain embodiments,in response to the questionable indication, the wireless charger 702 candelay the acceptance time window further back in time. For example, foran unquestionable indication (e.g., an impedance shift greater than orequal to a predetermined value), the acceptance time window may be 50ms-70 ms, but for a questionable indication (e.g., an impedance shiftless than the predetermined value), the acceptance time window may bedelayed (e.g., shifted) to 950 ms-970 ms (e.g., the time window in whichthe wireless charger 702 accepts a request for establishingcommunications from the chargeable device 704). Certain such embodimentsadvantageously reduce cross connections by allowing a wireless charger702 that detects an unquestionable indication of placement of achargeable device 704 in its charging region to attempt to connectbefore another wireless charger 702 that detects a questionableindication of placement of the chargeable device 704 in its chargingregion, thereby improving the probability that the correct wirelesscharger 702 will connect to the chargeable device 704 during the earlieracceptance time window.

FIG. 13 is a flow diagram of an example of a fifth resolution method1300 of facilitating avoidance of cross connection of a chargeabledevice 704 in communication with a wireless charger 702 in accordancewith certain embodiments described herein. In an operational block 1310,an acceptance time window is defined for the wireless charger 702. Theacceptance time window can occur after a chargeable device 704positioned within a charging region of the wireless charger 702 detectspower from the wireless charger 702. The acceptance time window can havea first endpoint at a first predetermined amount of time after power isapplied to the wireless charger 702 and a second endpoint at a secondpredetermined amount of time after power is applied to the wirelesscharger 702. For example, the first predetermined amount of time cancorrespond to a minimum expected delay between detecting power from thewireless charger 702 and enabling a data connection between thechargeable device 704 and the wireless charger 702 (e.g., 50 ms), andthe second predetermined amount of time can correspond to a maximumexpected delay between detecting power from the wireless charger 702 andenabling a data connection between the chargeable device 704 and thewireless charger 702 (e.g., 70 ms). In an operational block 1320, thewireless charger 702 receives a request to enable a data connection froma chargeable device 704.

In an operational block 1330, the wireless charger 702 detects anindication (e.g., an impedance shift of a transmit resonator impedance)of whether the chargeable device 704 is within the charging region ofthe wireless charger 702 and compares the indication to a predeterminedvalue (e.g., a minimum impedance shift of the transmit resonatorimpedance that is indicative of the chargeable device 704 being withinthe charging region of the wireless charger 702). In an operationalblock 1340, the acceptance time window is delayed (e.g., shifted) by apredetermined amount of time (e.g., 900 ms) if the detected indicationis inconclusive regarding whether the chargeable device 704 is withinthe charging region of the wireless charger 702 (e.g., the detectedimpedance shift is less than the predetermined minimum impedance shiftthat is indicative of the chargeable device 704 being within thecharging region of the wireless charger 702). In certain embodiments,the detection of the indication of whether the chargeable device 704 iswithin the charging region may occur before the request to enable a dataconnection is received by the wireless charger 702.

In an operational block 1350, the wireless charger 702 determineswhether the request occurs within the acceptance time window. In anoperational block 1360, the data connection can be accepted or rejectedin response to whether the request occurs within the acceptance timewindow or not. For example, if the request occurs during the acceptancetime window, the data connection can be accepted, and if the requestdoes not occur during the acceptance time window, the data connectioncan be rejected.

Delay or Rejection of Later Chargeable Devices

In certain embodiments (e.g., in which only one chargeable device 704 ispresent), the first attempt to create a data connection will be the mostvalid attempt. For example, the first attempt by a chargeable device 704within the charging region (e.g., on the pad) of a wireless charger 702will be an attempt to enable a data connection with the wireless charger702. In certain embodiments, the wireless charger 702 can accept thedata connection to the first chargeable device 704 attempting to enablea data connection with the wireless charger 702. The wireless charger702 can then either subsequently accept data connections from otherchargeable devices 704 (e.g., after a predetermined time delay) or canreject data connections from other chargeable devices 704. For example,for a wireless charger 702 configured to transfer power to multiplechargeable devices 704 concurrently, the wireless charger 702 can acceptthese subsequent data connection requests after a predetermined timedelay. For another example, for a wireless charger 702 configured totransfer power to a single chargeable device 704 at a time, the wirelesscharger 702 can reject these subsequent data connection requests.Certain such embodiments can improve the probability that the connectionwill be correct and not a cross connection condition.

FIG. 14 is a flow diagram of an example of a sixth resolution method1400 of facilitating avoidance of cross connection of a chargeabledevice 704 in communication with a wireless charger 702 in accordancewith certain embodiments described herein. In an operational block 1410,the wireless charger 702 receives a request to enable a data connectionfrom a chargeable device 704. In an operational block 1420, the wirelesscharger 702 determines whether any requests have been previouslyreceived before having received the request from the chargeable device704 (e.g., whether the received request is the first request received bythe wireless charger 702). In an operational block 1430, the wirelesscharger 702 accepts the data connection if no requests have beenpreviously received before having received the request from thechargeable device 704 (e.g., the received request is the first requestreceived by the wireless charger 702). If the wireless charger 702 isconfigured to transfer power to only a single chargeable device 704 at atime, the wireless charger 702 can reject subsequent data connectionrequests.

Delay or Rejection of Weaker Chargeable Devices

In certain embodiments, the chargeable device 704 having the strongestdata signal detected by the wireless charger 702 will be the chargeabledevice 704 within the charging region (e.g., on the pad) of the wirelesscharger 702. The wireless charger 702 can accept a data connection fromthe chargeable device 704 with the strongest data signal and can delayacceptance or can reject data connections from chargeable devices 704having weaker data signals. The strength of the data signal from achargeable device 704 can be measured the first time the data signal isdetected (e.g., based on a measurement of an instantaneous data signalstrength from the chargeable device 704) or can be measured after ashort, predetermined period of time after the data signal is detected(e.g., based on a measurement of an average data signal strength fromthe chargeable device 704). Using an average data signal strength cantend to negate the effects of jamming or outside interference. Theacceptance of the strongest data signal can improve the probability thatthe connection will be correct and not a cross connection condition.

FIG. 15 is a flow diagram of an example of a seventh resolution method1500 of facilitating avoidance of cross connection of a chargeabledevice 704 in communication with a wireless charger 702 in accordancewith certain embodiments described herein. In an operational block 1510,the wireless charger 702 receives one or more requests to enable a dataconnection from one or more chargeable devices 704. In an operationalblock 1520, the wireless charger 702 determines which request has thestrongest data signal of the one or more requests. In an operationalblock 1530, the wireless charger 702 accepts the data connectioncorresponding to the strongest data signal of the one or more requests.For requests that do not have the strongest data signal, the wirelesscharger 702 can delay acceptance or can reject the data connection.

The various operations of methods described above may be performed byany suitable means capable of performing the operations, such as varioushardware and/or software component(s), circuits, and/or module(s).Generally, any operations illustrated in the Figures may be performed bycorresponding functional means capable of performing the operations.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative logical blocks, modules, circuits, andalgorithm steps described in connection with the embodiments disclosedherein may be implemented as electronic hardware, computer software, orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. The described functionalitymay be implemented in varying ways for each particular application, butsuch implementation decisions should not be interpreted as causing adeparture from the scope of the embodiments of the invention.

The various illustrative blocks, modules, and circuits described inconnection with the embodiments disclosed herein may be implemented orperformed with a general purpose processor, a Digital Signal Processor(DSP), an Application Specific Integrated Circuit (ASIC), a FieldProgrammable Gate Array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm and functions described in connectionwith the embodiments disclosed herein may be embodied directly inhardware, in a software module executed by a processor, or in acombination of the two. If implemented in software, the functions may bestored on or transmitted over as one or more instructions or code on atangible, non-transitory computer-readable medium. A software module mayreside in Random Access Memory (RAM), flash memory, Read Only Memory(ROM), Electrically Programmable ROM (EPROM), Electrically ErasableProgrammable ROM (EEPROM), registers, hard disk, a removable disk, a CDROM, or any other form of storage medium known in the art. A storagemedium is coupled to the processor such that the processor can readinformation from, and write information to, the storage medium. In thealternative, the storage medium may be integral to the processor. Diskand disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer readable media. The processor andthe storage medium may reside in an ASIC. The ASIC may reside in a userterminal. In the alternative, the processor and the storage medium mayreside as discrete components in a user terminal.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

Various modifications of the above described embodiments will be readilyapparent, and the generic principles defined herein may be applied toother embodiments without departing from the spirit or scope of theinvention. Thus, the present invention is not intended to be limited tothe embodiments shown herein but is to be accorded the widest scopeconsistent with the principles and novel features disclosed herein.

1. A wireless charger for wirelessly charging a chargeable device, thewireless charger comprising: a wireless power transmitter configured togenerate a wireless charging field in at least one charging region; atransceiver configured to communicate with the chargeable device; and acontroller configured to: define a time window for receiving dataconnection requests from the chargeable device, receive a request toestablish a data connection with the chargeable device, determinewhether the request is received within the time window, and accept therequest to establish the data connection in response to determining thatthe request is received within the time window.
 2. The wireless chargerof claim 1, wherein the controller is configured to reject requests toestablish a data connection that are received outside the time window.3. The wireless charger of claim 1, wherein the time window is definedbetween a first time, after the chargeable device is positioned withinthe at least one charging region, at which the chargeable device isexpected to activate the data connection and a second time after thechargeable device is positioned within the at least one charging region.4. The wireless charger of claim 3, wherein the first time is a minimumexpected delay between when the chargeable device detects power from thewireless charger and when the chargeable device enables the dataconnection.
 5. The wireless charger of claim 3, wherein the second timeis a maximum expected delay between when the chargeable device detectspower from the wireless charger and when the chargeable device enablesthe data connection.
 6. The wireless charger of claim 3, wherein thefirst time is 50 milliseconds (ms) and wherein the second time is 70 ms.7. The wireless charger of claim 1, further comprising a detectioncircuit configured to detect whether the chargeable device is positionedwithin the at least one charging region and wherein the controller isfurther configured to receive a signal from the detection circuitindicating whether the chargeable device is positioned within the atleast one charging region.
 8. The wireless charger of claim 7, whereinthe controller is further configured to: determine, based on the signal,whether the chargeable device is positioned within the at least onecharging region by comparing the signal to a threshold value, and delaythe time window based on the signal being less than the threshold valueby a predetermined time value.
 9. The wireless charger of claim 8,wherein the detection circuit is configured to detect whether thechargeable device is positioned within the at least one charging regionbased on an impedance change of one or more components of the wirelesspower transmitter and wherein the threshold value is a minimum impedancechange of the one or more components of the wireless power transmitterindicative of the chargeable device positioned within the chargingregion.
 10. The wireless charger of claim 8, wherein the predeterminedtime value is 900 ms.
 11. A method of facilitating avoidance of crossconnection of a chargeable device is communication with a wirelesscharger, the method comprising: generating a wireless charging field inat least one charging region; defining a time window for receiving dataconnection requests from the chargeable device; receiving a request toestablish a data connection with the chargeable device; determiningwhether the request is received within the time window; and acceptingthe request to establish the data connection in response to determiningthat the request is received within the time window.
 12. The method ofclaim 11, further comprising rejecting requests to enable a dataconnection that are received outside the time window.
 13. The method ofclaim 11, wherein the time window is defined between a first time, afterthe chargeable device is positioned within the at least one chargingregion, at which the chargeable device is expected to activate the dataconnection and a second time after the chargeable device is placedwithin the at least one charging region.
 14. The method of claim 13,wherein the first time is a minimum expected delay between when thechargeable device detects power from the wireless charger and when thechargeable device enables the data connection.
 15. The method of claim13, wherein the second time is a maximum expected delay between when thechargeable device detects power from the wireless charger and when thechargeable device enables the data connection.
 16. The method of claim13, wherein the first time is 50 ms and wherein the second time is 70ms.
 17. The method of claim 11, further comprising: detecting, via adetection circuit, whether the chargeable device is positioned withinthe at least one charging region; and receiving a signal from thedetection circuit indicating whether the chargeable device is positionedwithin the at least one charging region.
 18. The method of claim 17,further comprising: determining, based on the signal, whether thechargeable device is positioned within the at least one charging regionby comparing the signal to a threshold value; and delaying the timewindow based on the signal being less than the threshold value by apredetermined time value.
 19. The method of claim 18, wherein thewireless charging field is generated by a wireless power transmitter,wherein detecting whether the chargeable device is positioned within theat least one charging region comprises detecting an impedance change ofone or more components of the wireless power transmitter, and whereinthe threshold value is a minimum impedance change of the one or morecomponents of the wireless power transmitter indicative of thechargeable device positioned within the charging region.
 20. The methodof claim 18, wherein the predetermined time value is 900 ms.